Variable pitch propeller controlled by wake



4 Sheets-Sheet V1 MoND, .m

J. H. HAMMOND, JR

VARIABLE FITCH PROPELLER CONTROLLED BY' WAKE Filed-April 17, 1941 Jan.5, 1943.

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Vel acfy of Slip -S'remm J. H. HAMMOND, JR 2,307,039

VARIABLE PITCH PROPELLER CONTROLLED BY WAKE Filed April 17, 1941 4sheets-sheet 2 l i l l l l l l l ll 5 8 l0 l2 l4 Vslociy af VesselINVENTOR JOHN HAYS HAMMOND, JR.

Jan- 5, 1943- J. H. HAMMOND, JR 2,307,039

VARIABLE FITCH PROPELLER CONTROLLED BY WAKE` Filed April 17, 1941 4Sheets-Sheet 3 INVENTOR i JOHN HAYS HAMMOND, JR.

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J. H. HAMMOND, ,1R 2,307,039

VARIABLE PITCH PROPELLER CONTROLLED BY WAKE 4 SheetsfSheet 4 Jan. 5,1943..V

Filed April 1'7, 1941 Patented Jan. 5, 1943 UNITED sTATEs PATENT OFFICEVARIABLE PITCH PROPEILER CONTROLLED BY WAKE John l-Iays Hammond,l Jr.,Gloucester, Mass. Application April 17, 1941, Serial No. 388,943

6 Claims. (Cl. 17o-163) This invention relates to variable pitchpropellers and more specifically to means for automatically varying thepitch of a propeller so as to maintain the most efficient propulsionconditions with a fixed power output under varying conditions of windand weather.

The invention further relates to means for indicating the speed of thevessel thru the water and the speed of the slip stream of the propellerand provides means responsive to the relationship between these twoindications to vary the pitch of the propeller blades in such a mannerthat the eiliclency of propulsion will be maintained at a maximum.

The invention provides means for automatically designating thetheoretical slip stream,

speed for various propeller and ship speeds and comparing the same withthe actual slip stream speed.

The invention also provides control mechanism for automatically varyingthe pitch of the propeller blades so as to bring the theoretical andactual slip stream speeds into agreement.

The invention further provides means for indicating the theoretical andactual slip stream speeds and manual means for controlling the pitch ofthe propeller blades so as to bring these two speeds into agreement.

The invention also provides means for varying the rate of change ofpitch of the propeller blades in accordance with the amount of change ofthe deviation between the theoretical and actual slip stream speed.

The invention also consists in certain new and original features ofconstruction and combinations of parts hereinafter set forth andclaimed.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself, as to its objects and advantages, the modeof its operation and the manner of its organization may be betterunderstood by referring to the following description taken in connectionwith the accompanying drawings forming a part thereof, in which Figure 1illustrates diagrammatically the system as applied to the ldrivingmechanism of a marine vessel.

Figure 2 shows the curve of relationship between the speed of the vesseland the speed o the slip stream of the propeller.

Figure 3 is an elevation partly in section of an integrating mechanismfor controlling the pitch of the propeller blades.

Figure 4 is a sectional view taken on line 4-4 of Figure 3.

Figure 5 is a sectional view taken on of Figure 3.

Figure 6 is a sectional view taken on line 6 6 of Figure 3.

line 5-5 Figure 7 is a top plan view of a modified form` of theinvention, and

Figure 8 is an elevation, partly in section, of the mechanism shown inFigure 7. v

Like reference characters denote like parts in the several figures ofthe drawings.

, In the following description and in the claims Y parts will beidentified by specific names for conmarine vessel is indicated at ii.The vessel is' driven by means of a propeller i2, which is provided withadjustable blades i3, and which has an outboard bearing in the rudderpost It. The propeller I2 is attached to the end of a hollow shaft I5which passes thru abearing it. A rudder I7 is mounted on the rudder postiii'. The shaft I5 is driven by a prime mover 2@ which may be of anydesired type such as a Diesel engine and is preferably provided with agovernor, not shown, for maintaining a constant speed of rotation.

'I'he blades I3 are connected to a variable pitch mechanism i8 which maybe of any well known and standard construction such as that manufacturedby the Escher Wyss Company of Zurich, Switzerland, the details of whichform no part of the present invention and are accordingly notspecifically set forth herein. This mechanism, in general, comprises arod i9 slidable longitudinally within the shaft i5 and connected tocontrol the pitch of the blades i3. The rod I9 is actuated by a piston21 in a fluid pressure. cylinder/Zia. Fluid for actuating the piston 2lis supplied by a pump 26 through a control valve 25 and a distributionvalve 25a which communicates with the cylinder 21a through ducts, notshown, in the shaft I5. A motor 2i rotates a worm 22 which operates tomove the upper end of a oating lever 23, which, in turn, is pivoted tothe end of a valve rod 24 which controls the valve 25. The piston 21 isconnected by a rod 28 to a collar 29 which is slidably mounted on theshaft I5 and engages the lower end of the lever 2 3 so that the positionof this end of the lever corresponds to the pitch of the blades |43.

The uppei end of the lever 23 is connected by a wire to an indicator 3|which shows the pitch at which the blades I3 are set. Stops 32 areprovided for limiting the maximum and minimum pitch of the blades I3.The fluid pump 26 is driven either by a motor 33 or a belt 35 from theshaft l5. A reservoir 36 and a supply tank 31 are provided for thenecessary fluid.

It is to be understood that other pitch control devices may be employedin place of that referred to above, for varying the pitch of thepropeller blades I3 in response to actuation of.,the motor 2|. Aparticular type is shown for purposes of illustration only.

Mounted on the hull is a speed indicating device lwhich may be of anywell known and standard construction such as that made by the KenyonInstrument Company of Boston and known as the Kenyon speedometer. Thiscomprises a strut 40 which is attached to a metallic bellows 4|containing fluid under pressure. The bellows 4| is connected by ahydraulic tube 42 to a speedometer 43 which is mounted in an integrator44 (Figure 3). It is to be understood that other types of speedometerdevices may be used if desired. A Pitot tube 46 is mounted on the rudderpost I4 and is connected by a tube 41 to a velocity indicator 48 whichis mounted at the top of the integrator 44.

The shaft of the velocity indicator 48 carries a Contact arm 49 whichcooperates with two semi-circular segments 50 and 5I which are mountedon, but insulated from, a gear 52 (Figure 4) which is secured to a shaft53 having a bearing yin the frame of the integrator 44. The gear 52meshes with a pinion 55 which is mounted on the shaft of a motor 56. Twoslip rings 51 and 58 are mounted on, but insulated from, the gear 52.The slip rings 51 and 58 are electrically connected to the segments and5| respectively. A battery 59 is provided for operating the motor 56 andis connected on one side to the contact 49 and on the other side to themotor 56. This motor is provided with two eld windings for causing it torotate in opposite directions. One of these windings is connected to acontact 6|) which engages the slip ring 51 and the other winding isconnected to a contact 6| which engages the slip ring 58.

The shaft 53 has secured to its lower end a bevel gear which meshes witha bevel pinion 66 which in turn meshes with a second bevel gear 61secured to a shaft; 68 which has a bearing in the frame 45. The bevelpinion 66 is mounted for rotation on a member 69 which is rotatablymounted on the shaft 68. The member 69 carries a contact 19 whichcooperates with a plurality of contact segments 1 |-16 which are mountedon but insulated from the frame 45.

The segments 1I and 16 are connected to two conductors 18 and 19 whichare connected to the ,reversing windings of the motor 2|. The segments12 and 13 are connected to two resistors 8D and 8| the other ends ofwhich are connected to the conductor 18. The segments 14 and 15 areconnected to two resistors 82 and 83, the other ends of which areconnected to the conductor 19. The common lead of the reversing windingsof the motor 2| is connected by a conductor 85 to one side of a battery86, the other side of which is connected to the blade of a threeposition switch 81. The center contact of this switch is connected tothe contact 10, the upper contact to the conductor 19 and the lowerContact t0 the conductor 18.

Secured to the lower end of the shaft 68 is a.

gear which meshes with a rack 9| (Figure 6) mounted for longitudinalmotion in two brackets 92 which form part of a member 93 which issecured to the upper end of a shaft 95 having a bearing in the frame 45.Rotatably mounted at the end of the rack 9| is a roller 96 which.engages the periphery of a cam 91 which is secured to the frame 45. Aspring 98 mounted between the rack 9| and the member 92 causes theroller 96 to be always held against the face of the cam 91.

Secured to the lower end of the shaft 95 is a follow-up system identicalto that described in connection with the velocity indicator 48 and thecorresponding parts of which bear the same numerals. The shaft of thespeedometer 43 carries a Contact arm 99 which cooperates with thesegments 59 and 5I of this follow-up system.

While a Kenyon speedometer and a Pitot tube have been shown formeasuring the velocities of the vessel and the propeller slip-streamrespectively, it is to be understood that any other suitable types ofvelocity recorders may be used in their place if -so desired.

In the operation of the form of the invention shown in Figures 1 to 6the pitch of the blades I3 is set at the'normal operating angle for thespeed at which it is desired to operate the vessel. The setting of theblades |3 is accomplished by moving the blade of the switch 81 into theupper or lower position which will cause the motor 2| to move the upperend of the lever 23 to the left or right to increase or decreasethepitch in a well known manner, the angle of pitch being indicated by thepointer of the indicator 3|.

The vessel is then brought up to the desired speed at which time thestrut 40 will receive a certain amount of pressure dueto the motion ofthe vessel thru the water. This pressure will be transmitted by thehydraulic cylinder 4| and tube 42 to the speedometer 43, the contact arm99 of which will rotate in a clockwise direction, as seen from above, anamount proportional to the speed of the vessel.

As the contact arm 99 rotates it will engage the segment 56 causing anelectrical circuit to be closed from the battery 59,` contact 99,segment 5D, slip ring 51, contact 60 and Winding of motor 56 back tobattery 59. This will cause the motor 56 to be rotated in such adirection that the gear 52 will be rotated clockwise. This rotation willcontinue until the insulation betweenl the segto the speed of thevessel.

The motion of the gear 52 will be transmitted by the shaft 95 to themember 93, which in turn will rotate the rack 9| and roller 96. As thelatter rolls over the face of the cam` 91, it will be moved away fromthe axis of the shaft 95 thus causing the rack 9| to rotate the gear 90relative to the member 93 Aan amount proportional to the radial motionof the roller 96. It is thus seen that the relative motion of the gear90 and shaft 68 with respect to the member 93 and shaft 95 is dependenton the shape of the cam 91.

If the cam 91 were circular in'shape the shaft 68 would move exactly insynchronism with the shaft 95, as there would be no relative motionbetween the rack 9| and the member 93. The shape of the cam 91 isdetermined by the relative velocity of the vessel thru the water and thevelocity of the slipstream of the propeller for the most etllcientpropulsion with a given horsepower output under varying conditionsofwind and weather. An example of this relationship is depicted in Figure2 in which the curve |0| is plotted with speed of vessel as abscissa andvelocity of slip-stream as ordinates. This curve may be obtained eitherfrom theoretical data or from actual test runs of the vessel and will bedifferent for each vessel and therefore the cam 91 will be different foreach vessel and may vary for different conditions of the same vesselsuch as loading, horsepower out-put to be maintained on run, etc. Itmay, therefore, be necessary-to have a set of cams for each vessel whichcan be put in place of cam 91 to suit the conditions of the variousruns.

As already stated the motion of the shaft 95 is proportional to thespeed of the vessel thru the water as determined by the speedometer 43.The motion of the shaft 68, however, as determined by the shape of thecam 91 will give the theoretical speed that the propeller slip streamshould have under the prevailing conditions of wind and weather. Inother words, the position of the shaft 68 indicates the velocity thatthe propeller slip stream should have for the most efcient propulsion ofthe vessel with the predetermined horsepower out-put and under theprevailing conditions of wind and Weather.

In order to determine whether the actual slipstream of the propeller hasthis theoretically eftlcient velocity the speed of the slip-stream isde'- termined by the Pitot tube 46 and is measured by the velocityindicator 38. 'I'he contact arm 49 operates a follow-up system similarto that described in connection with the speedometer 43,'

similar parts being designated by the same numerals. The gear 52 andtherefore the shaft 53 will rotate an amount proportional to the speedof the propeller slip-stream, only in this case the rotation withincrease of velocity will lbe counterclockwise, as seen from above.

As the gear 65 is attached to the shaft 53, itl

will rotate an amount proportional to the actual slip-stream velocity ina counter-clockwise direction and as the gear 61 is attached to theshaft 68 it will rotate an amount proportional to the theoreticalslip-stream velocity in a clockwise direction. If the actual slip-streamvelocity is 'I'his would cause'a rotation of the member 69 and thereforeof the contact 10 in a counter-clockwise direction causing this contactto engage .the segment 14 which will close a circuit from the battery 86thru the resistance 82 to the motor 2| causing it to rotate slowly in adirection to move the upper end of the lever to the right, for example.'I'his will move the valve to the right, which will allow -uidunderpressure to pass from the pump 26 to the cylinder 21a by means of theducts in the shaft I5. This will actuate the piston 21 which, by meansof the rod I9 and the link mechanism, will cause the propeller blades I3to slowly decrease their pitch. This will decrease the actualslip-stream velocity thus causing the gear 65 to rotate in a clockwisedirection. This in turn will rotate the member 69 in a clockwisedirection until the contact 10 rests again on the insulation between thesegments 13 and 14 thus stopping the motor 2|.

If the vessel should increase its speed due to a following wind or otherfavorable conditions the actual speed of the slip-stream would be lessthan the theoretical and the reverse action would take place, -thuscausing a gradual increase in the pitch of the propellers until theactual and theoretical slip-stream speeds became identical at which timethe contact 10 would againrest on the insulation between the segments 13and 14 at which time the motor 2| would stop` If the changed conditionscause a rapid change of speed so that the contact 10 engages either`segment 12 or 15, then the resistor 80 or the contact 10 engages eithersegment 1| or 16 then equal to the theoretical slip-stream velocity, the

I head winds and be slowed down the actual slipstream velocity asmeasured by the Pitot tube 46 might not decrease as the theoreticalvelocity as determined by the speed of the vessel. In this event, thegear 61 would rotate thru a greater angle in a counter-clockwisedirection than the gear 85 would rotate in a clockwise direction.

no resistance will be thrown in the circuit of the motor 2| and it willrotate at its maximum speed, thus changing the propeller pitch at amaximum rate. The stops 32 are provided so that the propeller pitch isprevented from exceeding certain limits beyond which it could notoperate efliciently under any conditions.

In this way the pitch of the propeller blades i3 is varied to cause thepropeller to operate at the maximum possible efficiency for the existingconditions of'wind and weather utilizing the rated horsepower of ltheprime mover. The rate of change of pitch will vary in accordance withthe rate of change of speed of the vessel so that with a gradual changeof speed there will be a slow change of propeller pitch, thus preventingviolent changes of pitch which would cause undue strain on the drivingmechanism, disagreeable vibrations and ineciency of the propeller.

On both of the recording instruments 43 and 46, the motion of thecontact arms 99 and 49 indicate the respective velocities in accordance-with the square law. In this way the two contact arms will haveidenticalangular positions for equal velocities. If, however, differenttypes of recording instruments vare used which have different types ofscalereadings, it will be necessary to insert a compensating mechanismbetween the upper gear 52 and the gear 65 which would correct thisinequality and bring the motions of the two gears 65 and 61 to acommonscale.

This may be accomplished by the use of a cam mechanism similar to thatalready described in connection with parts -91 and which would be up toand including the shaft 68 is identical to that already described andcorresponding .parts have been given the same numerals. In this form ofthe invention the shaft 68 has been extended so that it protrudes abovethe top of the frame 45 and has secured thereto a pointer |02 whichregisters with a scale |03 secured to the top of the frame 45. Rotatablymounted on the shaft 60 and resting against a shoulder |05 providedthereon is a gear |06. Secured to this gear is a sleeve |01 whichsurrounds the shaft 68 and which protrudes above the top of the frame45. Secured to the sleeve |01 is a second pointer |08 which alsoregisters with the scale |03.

Mounted on, but insulated from, the gear |06 is a circular contactsegment IIO in which is inserted a small block of insulation III.Mounted on, but insulated from the shaft 68 is a sleeve of conductingmaterial II2 to which is attached a contact I|3 which engages thesegment IIO. Two brushes II5 and II6 engage the segment |I0 and thesleeve II2 respectively and are in the circuit of a bell II1, abattery'II8 and a switch IIB.

Mounted on the frame 45 is the velocity indicator 48 together with thefollow-up system as already described the parts of which bear the samenumerals as the corresponding parts in the previous figures. The gear 52of this follow-up system meshes with the gear |06. The battery 86 andswitch 81 are mounted on the top of the frame 45 and are connected bythe conductors 18, 19 and 85 to the motor 2|. The blade pitch indicator3| is located adjacent to the apparatus so that it can be readily viewedby the man operating the switch 81.

Operation of Figures 7 and 8 In the operation of the modilied form ofthe invention shown in Figures '1 and 8 the shaft 68 and therefore thepointer |02 will indicate on the scale I 03 the theoretically mosteilicient propeller, slip-stream speed for the speed at which the vesselis running under the prevailing conditions of Wind and.weather with therated horse power of the prime mover 20. This is accomplished in amanner similar to that already described in connection with the previousgures. The actual speed of the propeller slip-stream will be measured bythe Pitot tube 46 and will be indicated by the position of the contactarm 48. The motion of this arm will be transmitted by the follow-upsystem and gears 52 and |06 to the pointer |08 which will indicate onthe scale |03 the actual slip-stream speed.

If these two pointers do not coincide it will indicate that the actualslip-stream speed is not what it should be for maximum efficiency andtherefore the pitch of -the blades I3 should be changed. I-f, forexample, the pointer |08 indicates a higher slip-stream speed than thepointer |02, it will show that the actual slipstream speed is greaterthan the theoretical and therefore the pitch of the propellers should bedecreased. This is accomplished, as already described, by moving theswitch 81 into the lower position where it is held 4until the pitch hasbeen decreased suiliciently to reduce the actual slipstream speed to thetheoretical speed as indicated by the pointer |08 moving into line withthe pointer |02, as shown in Figure 7. The pitch of the blades underthis condition is indicated by the pointer of the indicator 3|. If theactual slip-stream speed is less than the theoretical, the pitch of theblades I3 is increased lby moving the switch 81 to its upper positionuntil the two pointers |02 and |08 are in line.

When these two pointers |02 and |08 are in' line indicating that thepitch of the blades I3 is correct for the prevailing conditions of windand weather, the switch I I9 is closed. As under these conditions thecontact I|3 is resting on the insulation I II the circuit to the bellII1`wi1l be open.- Ii' conditions change, however, so that the actualslip-stream speed is not the same as Ithe theoretical, the contact II3will move oif the insulation III and engage the contact segment I I0,thus closing the circuit to the bell I I1 which will be sounded thusapprising the navigator of the condition who will then change thepropeller pitch accordingly.

Although only a few of the various forms in which this invention may beembodied have been shown herein, it isv to be understood that theinvention is not limited to any specific construction but might -beembodied in various forms without departing from the spirit of theinvention or the scope of the appended claims.

What is claimed is:

1. In a system for driving a vessel, a variable pitch propeller havingblades, means directly responsive to the speed of the propeller slipstream with respect to the vessel, means responsive to the speed of thevessel through the water to designate the proper theoretical slip streamspeed at said vessel speed, and means comparing the actual andtheoretical slip stream speeds.

2. In a system for driving a vessel, a variable pitch propeller havingblades, means ldirectly responsive to the speed of the propeller slipstream with respect to the vessel, means responsive to the speed of thevessel through the water to designate the proper theoretical slip streamspeed at said vessel speed, means comparing the actual and theoreticalslip stream speeds, and means actuated by said comparing means tocontrol the pitch of said blades in a sense to maintain a predeterminedrelationship between said actual and theoretical slip stream speeds.

3. In a system for driving a vessel, a variable pitch propeller havingblades, means directlyv responsive to the speed of the propeller slipstream with respect to the vessel, means responsive to the speed of the-vessel through the water to designate the proper theoretical slipstream speed at said vessel speed, means comparing the actual andtheoretical slip stream speeds, and means actuated by said comparingmeans to control the pitch of said blades in a sense to maintain apredetermined relationship between said actual and theoretical slipstream speeds and at a speed.

travel of said vessel, indicating means actuated by and as a function ofthe response of said last means, means responsive to the slip streamspeed and indicating means actuated by said last means, said indicatingmeans being arranged for simultaneous reading for comparing theindicated speeds.

5. In a vessel having a propeller producing a slip stream, meansresponsive to a function of the v by the combined effect of said rst twomeans to indicate the relationship thereof.

6. In a vessel having a variable pitch propeller producing a slipstream, means responsive to a function of the speed of travel of saidvessel, means responsive to the slip stream speed, and means actuated bythe combined eiect of said first two means to vary the pitch of saidpropeller in a sense to maintain a predetermined respeed of travel ofsaid vessel, means responsive 10 lationship therebetween.

to the slip stream speed, and means actuated JOHN HAYS HAMMOND, JR.

